Spinal muscular atrophy (SMA) is a form of motor neuron disease, most commonly caused by a mutation in the survival motor neuron 1 gene (SMN1) which results in a wide disease spectrum affecting children and adults. It is an autosomal recessive disorder and is therefore caused by inheritance of a mutated gene from each parent. All forms of SMA have an estimated combined incidence of 1 in 6,000 to 1 in 10,000 live births, with a carrier frequency of 1/40 to 1/60. The patient registry aims to facilitate a questionnaire-based research study in order to better characterise and understand the disease in the UK and in Ireland. Entry is via self-registration over a secure internet connection (https://www.sma-registry.org.uk/). Online, patients are asked to read an information sheet about the research project and then indicate their consent to demonstrate willingness to participate. Following online consent, subjects will be entered into the registry. This is an on-going database and all participants are invited to update their information on a biannual basis.